Gathering the letter likely increases friction for capital moving to your deal and reduces the audience for investments because they're unwilling to surrender data to promoters or their advisers are unwilling to write the letter for liability reasons.

Any Statistics/data?

So what you get should be taken to your attorney with the highlights to ensure you don't lose money, time or your reputation.You can't get a good education from someone who doesn't have one. :)

Out of that $540 you're paying:TaxesInsuranceUtilities (at least when vacant)Legal costsCPA costs (or, higher taxes if you try to DIY your taxes)Vacancy (even if just for a week or two during turnovers)Routine maintenance (inevitable, stuff really does break)Make ready costsTenant damage in excess of security depositsCapitalThe 50% number is well supported by large data sets.

Another bit of data that will be useful.

I'm wondering what steps I could take to ensure that this is a good area to rent in.

You need a full pre-approval, where an underwriter has reviewed all your data (tax returns, cash reserves, etc.) and said it's a go.You do NOT want to get stuck in a hard money loan.

So with limited time paying off debt may not matter as much as ensuring an ongoing income.

You can use a Shellac base primer which should encapsulate the staining AND odor (Cover Stain just covers the stain not odor) but you should really wash the walls down with at least a TSP substitute prior to priming and painting to ensure a good bond.

Provided there is sufficient and current data, this could tell you the current market value.